Rutherfurd was born and raised in New York City, New York. She is the daughter of Winthrop Rutherfurd Jr. and Mary Spratt (née Kernan) Rutherfurd, himself the grandson of New York socialite Winthrop Rutherfurd (1862–1944). Her paternal uncle is Lewis Polk Rutherfurd (b. 1944) who was married to Janet Jennings Auchincloss (1945–1985), the half-sister of former First Lady Jacqueline Kennedy Onassis, from 1966 until her death in 1985.

Rutherfurd made her television debut in 1999 as a series regular on the short-lived CBS sitcom Work with Me opposite Nancy Travis and Kevin Pollak. Later, she was a regular cast member on The Ellen Show and Married to the Kellys. She played Christine “New Christine” Hunter on the CBS sitcom The New Adventures of Old Christine which aired from 2006 to 2010 and also starred Julia Louis-Dreyfus. She had the lead role in Work Mom.

She attended Sacred Heart school on the Upper East Side. She also attended St. Mark’s School in Southborough, Massachusetts. She then attended the University of Southern California in Los Angeles. She lives in Los Angeles with her husband, Rollin McCulloch “Loch” Gallagher IV, whom she married in 2003, and their daughters, Grace and Lila.